In a common method for manufacturing magnetic recording heads for use in disk drives, each magnetoresistive sensor, or reader, and its associated magnetic writer is fabricated on a surface of a wafer as one head in an array of heads arranged in rows and columns. After completion of the wafer fabrication process, the wafers are sawed into bars, with each bar containing one row of heads. Each bar is then lapped very precisely to machine a critical “stripe height” reader dimension by mechanically removing one edge of a relatively high “stripe” feature defined lithographically in the wafer process.
One problem with this mechanical lapping process is that the magnetoresistive sensor stripe typically consist of several thin layers of magnetic material that readily oxidize when exposed at the lapped surface. In addition, the layers of the sensor can be mechanically disturbed at the lapped edge. The performance of the magnetoresistive sensor is critically dependent on the stripe's proximity to the lapped, or “air bearing surface” of the head, and on the compliance of the stripe height to tight dimensional specifications. Thus, any chemical or mechanical damage to the lapped edge of the stripe results in degraded sensor performance. Mechanical damage is particularly harmful to the performance of “tunneling magneto resistive” or TMR sensors because such sensors rely on a exceedingly thin, and easily damaged insulating quantum tunneling barrier.
A method and apparatus are needed that provide a precisely controlled stripe height and that provide freedom from chemical and mechanical damage due to lapping. Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.